Assembling Colloids, Like Computer Game Graphics

Their findings appeared in the June 8th issue of the prestigious journal, Nature Communications.

A recent study by an international team of researchers, affiliated with UNIST has announced that they have succeeded in demonstarting spontaneous and directed assembly of colloid particles.

This breakthrough comes from a research, conducted by Professor Steve Granick (School of Natural Science, UNIST) of IBS Center for Soft and Living Matter in collaboration with Professor Lingxiang Jiang from Jinan University, Guangzhou, China.

There has been an ongoing endeavour in chemistry and materials science to assemble building blocks like molecules and colloids into organized structures to ultimately match or even surpass nature’s precision, complexity and functionality. The key to spontaneous and directed assembly is to encode the desired assembly information to building blocks in a programmable and efficient way, but this still has been an elusive task due to the following limitations.

The raster/vector concept in computer graphics and assembly.

The research team notes that the current vector assembly does not occur spontaneously but is directed by optical tweezers, so the vector structures cannot be produced in large quantity and ‘click assembly’ cannot be realized. The vector approach is, however, by no means limited to directed assembly. It is possible to mix a trace amount of carefully designed pin molecules with a large amount of dummy molecules so that molecular assemblies can be massively produced and be switched between micelles, vesicles and tubes upon simple clicks.

Moreover, chemical fixation of the vector structure is envisioned to be feasible given a number of well-established methods such as sintering, polymer grafting and cross-linking, and capillary condensation. Once permanently fixed, the vector structures can be subject to translational or rotational operations or layer-by-layer stacking to construct 3D structures.

The colloidal monolayer.

According to the research team, the present assembly process is relatively time-consuming especially for large structures, but one can reduce consumption of time and labour by developing automated assembly approaches. Although those next steps are beyond the scope of this paper, they anticipate the vector assembly will open new doors for self-assembly and directed assembly.